This invention is directed to an improved digital display electronic wristwatch, and in particular to an improved electronic wristwatch having a calculator circuitry that is operated by the time standard signals utilized to operate the timekeeping circuitry of the wristwatch.
The popularity of table size and hand held calculators has increased in recent years due to their portability. The utmost portability is obtained when a calculator is included in an electronic wristwatch. Nevertheless, efforts to include a calculator in an electronic wristwatch have been less than completely satisfactory due to the size of the electronic wristwatch and the manner in which the calculator circuitry has been added. Specifically, efforts to combine an electronic wristwatch with an electronic calculator have been directed at providing entirely independent timekeeping circuitry and calculator circuitry and only utilizing certain of the input switches to operate the respective timekeeping and calculator circuits, and further providing a single display for displaying either the timekeeping information or calculator information. In such an arrangement, no thought is given to the interrelationship between the respective circuits of the timekeeping circuitry and the calculator circuitry, which therefore prevents the elimination of particular circuits in the timekeeping circuitry and calculator circuitry that would permit further miniaturization of the electronic wristwatch. Accordingly, the electronic wristwatch of the instant invention is characterized by the common usage of many circuits for processing both calculator information and timekeeping information.